High Speed Downlink Link Packet Access (HSDPA for short) is a technique proposed by the 3rd Generation Partnership Project (3GPP for short) in Release-5, which is used to improve network data throughput in the downlink direction (from the network to the terminal), and the cell and the single user downlink peak rate designed by it can reach 14.4 Mbps. Then, in order to make the downlink peak rate higher, a new technology, High Speed Packet Access Evolution (HSPA+) is introduced, these technologies include the downlink 64 Quadrature Amplitude Modulation (QAM) high-order modulation and Multiple Input Multiple Output (MIMO for short) antenna technology proposed in Release-7, the Double-carrier (DC) HSDPA technology proposed in the Release-8, the DC HSDPA+MIMO technology proposed in the Release-9, and the Four Carrier HSDPA (4C HSDPA) technology proposed in the Release-10. However, because the HSDPA does not support soft switching, in order to improve the user experience on the cell edge, the Release-11 starts to research on the multi-point transmission technology for Wideband Code Division Multiple Access (WCDMA) HSDPA. One multi-point transmission technology scheme therein is Single Frequency Dual Cell (SF-DC), which includes dual-data stream transmission scheme SF-DC Aggregation and single-data stream transmission scheme SF-DC Switching. The SF-DC Aggregation refers to two co-frequency cells (referred to as a primary serving cell and a secondary serving cell) using the HSDPA technology under the same NodeB or different NodeBs transmitting different data streams to the same UE in the same Transmission Time Interval (TTI), thereby improving the data throughput when the user is at the cell edge. The SF-DC Switching refers to selecting a cell with better signals from both co-frequency cells (referred to as a primary serving cell and a secondary serving cell) under the same NodeB to transmit a data stream to the UE. The SF-DC technology requires a user starting the SF-DC to monitor High Speed Shared Control Channel (HS-SCCH) of two co-frequency primary and secondary serving cells, and feeds back jointly encoded Acknowledgement/Negative Acknowledgement (ACK/NACK) and Channel Quality Indicator (CQI) indication to both co-frequency primary and secondary serving cells in the uplink direction, wherein, the indication is transmitted in the High Speed Dedicated Physical Control Channel (HS-DPCCH). At present, the 3GPP specification 25.211 specifies occasions when the UE transmits the HS-DPCCH, that is, the HS-DPCCH channel is started to be transmitted about 7.5 slots (i.e., 19200 chips) after the UE receives the High-Speed Physical Downlink Shared Channel (HS-PDSCH), as shown in FIG. 1.
Since in the SF-DC system, there exists a frame offset in the downlink channels transmitted by the primary and secondary serving cells and the air broadcast delays of both cells are different, it results in that the UE receives the HS-PDSCH channel from the primary and secondary serving cells respectively at different times. According to the existing specification, the UE cannot transmit the jointly encoded ACK/NACK and CQI indication to the primary and secondary serving cells with different frame offsets at the same time. In order to enable the UE to transmit the ACK/NACK and CQI indication to both the primary and secondary serving cells of the SF-DC at the same time, the 3GPP is doing research on the following several schemes at present:
the first scheme is to compress the time during which the UE transmits the HS-DPCCH, that is, the UE can transmit the HS-DPCCH channel after 4.5 slots-7.5 slots after receiving the HS-PDSCH channel, and this scheme needs the network side to pair the HS-PDSCH subframes of the primary and secondary serving cells according to the frame timing offset of the primary and secondary serving cells reported by the UE, as shown in FIG. 2;
the second scheme is to compress the time during which the NodeB decodes and processes the HS-DPCCH, and this scheme also needs the network side to pair the HS-PDSCH subframes of the primary and secondary serving cells according to the frame timing offset of the primary and secondary serving cells reported by the UE, as shown in FIG. 3;
the third scheme is to equalize and compress the time during which the UE transmits the HS-DPCCH and compress the time during which the UE decodes and processes the HS-DPCCH, and this scheme also needs the network side to pair the HS-PDSCH subframes of the primary and secondary serving cells according to the frame timing offset of the primary and secondary serving cells reported by the UE, as shown in FIG. 4.
All above three schemes are based on solutions that, when the number of Hybrid Automatic Repeat Request (HARQ) processes of the UE is 6 per serving cell and the UE which activates the multi-stream transmission needs to be scheduled every TTI. While the number of HARQ processes of the UE which is specified by the specification can be 1-8 per serving cell, and when the number of HARQ processes is not 6 per serving cell, the above three schemes have no application value. In addition, when the UE which activates the multi-stream transmission needs not to be scheduled every TTI, the above three schemes also have no application value. Meanwhile, all above various schemes have a large influence on the hardware of the terminal or the NodeB, thereby increasing the implementation cost. If the first scheme or the third scheme is used, there will also exist a relatively large influence on the existing specification.